Returning visitors probably noticed that this blog has a new look. The other thing that's different is that I've installed Disqus for comments. Write a response, and click "post as" to get the following:
Blogger's native comment system allows people to log in and comment with a Google account or OpenID. Disqus allows those too, plus Yahoo, Facebook and Twitter, in addition to users with Disqus accounts Plus, all existing comments have been imported into Disqus. In addition, Disqus syncs comments with Blogger, so if I ever switch back the comments will still be there.